1. Field of the Present Invention
The present invention relates to hexahydrophthalate based compound and a process for producing the same. More particularly, the present invention relates to hexahydrophthalate based compound adapted to use as a plasticizer that contains no phthalic acid and benzoic acid, possess physical properties superior to DEHA and DINA in transparency and adhesion and is friendly to organisms and the environment, and a process for producing the same.
2. Description of Prior Art
As known in the art, plasticizers provide capability of being processed, flexibility, and electrical insulation property to resins, such as PVC resin, during finishing thereof. Besides, plasticizers present swelling effect and are dissolvable in resins to form even films. As compared with resins without plasticizers, resins with plasticizers are advantageous to lower thermoplastic temperature, improve flowing and forming ability when heated up, enhance elasticity and reduce hardness.
Presently, the most popular plasticizers are those made of phthalic anhydride, such as Di-2-ethylhexyl phthalate (DOP) and Di-iso-nonyl phthalate (DINP). However, according to researches and reports, such plasticizers can bring environmental hormone-related problems and therefore are ecologically adverse. On the other hand, plasticizers referred to Di(2-ethylhexyl)adipate (DEHA) made of adipic acid are suspected to be harmful to human liver.
As to food packing materials, adhesion and transparency of PVC films are highly required. Food packing materials added with DEHA plasticizers are officially banned for being suspected to be harmful to human health. Food-packing materials added with DINA plasticizers feature improved migration of plasticizers due to increased molecular weight, and yet are flawed by deteriorated adhesion.
In the known prior art, U.S. Pat. No. 3,110,603 discloses polyalkylene glycol dibenzoate highly miscible with PVC resin but inefficient in plasticizing due to benzene rings structurally existing therein. In Publication No. WO2005023926, a diethyleneglycol ester based plasticizer is proposed, wherein the compound is produced from benzoic acid with excessive acidity. However, the compound contains benzene rings and has a relatively low molecular weight, tending to be volatile during a finishing process.